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Ring Main at Consumer unit
dcbwhaley
55 Posts
Question
My daughter has just had an electrical safety check done and I suspect that the electrician has been over zeleous..
Would anyone care to comment.

There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout.
He has graded this C1.   Now my opinion is that that does not present an  an immediate threat to the safety of personell
It needs fixing but surely only a C2?

More intriguing.  He gives a C3 to the ring circuit because the two legs enter the consumer unit through separate knock outs.  I can't find that in the regs

And finally an old chestnut which has been discussed before.   A C3 because two radial "circuits" are served by a single breaker..  I have always argued that the definition of a circuit is that it is served by a single breaker.  Certainly if both radials were brought to a junction box outside the CU and then connected to the breaker by a single cable it would meet the definition of a radial..

Thanks for your attention
 
157 Replies
Zoomup
3131 Posts
"More intriguing.  He gives a C3 to the ring circuit because the two legs enter the consumer unit through separate knock outs.  I can't find that in the regs".

If one leg of a ring final circuit enters with L, N and C.P.C. through one hole, and the second leg with its L,N and C.P.C. enters through another separate hole all is o.k. There is no problem at all.

Z.
Zoomup
3131 Posts
"And finally an old chestnut which has been discussed before.   A C3 because two radial "circuits" are served by a single breaker..  I have always argued that the definition of a circuit is that it is served by a single breaker.  Certainly if both radials were brought to a junction box outside the CU and then connected to the breaker by a single cable it would meet the definition of a radial.."

Is there any chance of overloading here?

Z.
dcbwhaley
55 Posts
No.  But that is given as separate C2
ebee
1199 Posts
"Is there any chance of overloading here?" OCPD should take care of that no matter how many radials make that circuit
Chris Pearson
2686 Posts
dcbwhaley:
There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout.
He has graded this C1.   Now my opinion is that that does not present an  an immediate threat to the safety of personell
It needs fixing but surely only a C2?

I agree - C1 would be for bare copper and potentially isolate or fix there and then, but either way, it needs to be fixed. IMHO tails should enter through a gland for security. The lack of the outer sheath troubles me more than the lack of a grommet.

Colin Haggett
117 Posts
Out of his depth comes to mind… C2 for the tails unless you can stick your finger in and touch something live. We have final ring circuits now because we love a name change but seriously it’s just something he’s made up must be loads of legs passing through different holes just in back boxes. As to two radials on one breaker it’s again perfectly ok.
dcbwhaley
55 Posts
I agree.  I have advised her to have a new 10th edition CU fitted with more ways so that each "circuit" can have its own fuse. Having upstairs and downstairs lights on one breaker is not good practice if not a code
aligarjon
120 Posts
dcbwhaley:
I agree.  I have advised her to have a new 10th edition CU fitted with more ways so that each "circuit" can have its own fuse. Having upstairs and downstairs lights on one breaker is not good practice if not a code

We are currently on the 18th edition.

Gary

perspicacious
624 Posts
My daughter has just had an electrical safety check done and I suspect that the electrician has been over zeleous..
Would anyone care to comment.


I find it odd that only three items have been questioned out of what I suspect are many more recorded defects. The end result is still unsatisfactory and remedial work is required.

Regards

BOD
Looking at these things, the inspector is not competent to do an EICR, and so none of the observations can be believed at all. dcbwhaley should note that a new CU is exactly what this inspector wants to fit, and none of the points make that necessary. You need to not pay for this EICR (and if you have one I would like a copy for research purposes) and to have a new one by a suitably qualified electrician, ask for a C&G 2391 certificate for the inspector, suitable insurance certificates for PI and PL liability, and a full training record. You may then find that little or no work is required.
my email davezawadi (at) yahoo.co.uk, thanks.

David CEng.
Sorry BOD, I don't agree that you have identified the problem.
Kind regards
David
dcbwhaley
55 Posts
There are other recorded defects and I intend to rectify most of them.
But that does not detract from the fact that the tails to the CU are a C2 not a C1
dcbwhaley
55 Posts
You are welcome to a copy.  How do I get it to you?
My daughter has already paid for the report and she is of a character that abhors fuss.
I will  try to persuade to use another electrician to any remedial work.   I am competent to do most of it myself but am unhappy to deal with live meter tails

I think that a  new CU with RCBOs  would be a worthwhile upgrade even if what you say is tru
Chris Pearson
2686 Posts
dcbwhaley:
I am competent to do most of it myself but am unhappy to deal with live meter tails

You gave the impression of knowing what you are about until mentioning dealing with live tails. I just wouldn't even if my livelihood depended upon it. My life is worth more than my livelihood.

Just pay the DNO to isolate and reconnect when the work is done.

perspicacious
624 Posts
Sorry BOD, I don't agree that you have identified the problem.

I was questioning the selective aspects David, not the competence aspect !

Regards

BOD
dcbwhaley
55 Posts
I am always puzzled why the DNO do not provide an isolator switch.  Every other service into my house - water, gas, oil - has an isoliating valve.  Is pulling the DNO fuse an acceptable way of isolating?
Sparkingchip
4245 Posts
The question isn’t if the installation is shoddy, it’s just how shoddy is it?

 
Zoomup
3131 Posts
ebee:
"Is there any chance of overloading here?" OCPD should take care of that no matter how many radials make that circuit

Indeed, but we are considering a reliable circuit with no nuisance tripping off of say fridges or freezers.

314.1

133.2



Z.

Zoomup
3131 Posts
Chris Pearson:
dcbwhaley:
There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout.
He has graded this C1.   Now my opinion is that that does not present an  an immediate threat to the safety of personell
It needs fixing but surely only a C2?

I agree - C1 would be for bare copper and potentially isolate or fix there and then, but either way, it needs to be fixed. IMHO tails should enter through a gland for security. The lack of the outer sheath troubles me more than the lack of a grommet.

"There is no grommet where the meter tails enter the consumer unit and the outer insulation stops just short of the knockout."

Does this mean that bare copper is visible and could be touched, or does it mean that the insulated and sheathed tail has its sheathing cut short and the inner insulation is showing, perhaps to identify the tail's function?

I think that we need to be told.

Z.

Zoomup
3131 Posts
dcbwhaley:
I agree.  I have advised her to have a new 10th edition CU fitted with more ways so that each "circuit" can have its own fuse. Having upstairs and downstairs lights on one breaker is not good practice if not a code

Each circuit on a separate R.C.B.O. is the best most reliable option.

Z.

Colin Haggett
117 Posts
Depends where you live and age of property for isolators. You can get isolators fitted by your energy supplier. The DNO only go as far as the head the supplier to the meter or isolator if fitted. Only certain DNOs will permit main fuse removal but will require resealing.
Zoomup
3131 Posts
dcbwhaley:
My daughter has just had an electrical safety check done and I suspect that the electrician has been over zeleous..
Would anyone care to comment.

There is no grommet where the meter tails enter the consumer unit and the outer insu

And finally an old chestnut which has been discussed before.   A C3 because two radial "circuits" are served by a single breaker..  I have always argued that the definition of a circuit is that it is served by a single breaker.  Certainly if both radials were brought to a junction box outside the CU and then connected to the breaker by a single cable it would meet the definition of a radial..


 

What are the two circuits? Are they two lighting circuits which have been put onto one M.C.B. for some reason or another, where initially they were two separate circuits on two separate breakers.

314.1

Z.

ebee
1199 Posts
I know what you mean Zoom. I have a friend who is a NIC approved contractor and his comments of "circuits doubled" in the consumer unit causes me always to inform him there is no such thing. I keep reminding him that a radial can take any form, not just from fuseway then one to tother to tother etc till the end but also teed and treed in any config including two or more conductors in the fuseway . He`s happy with all of that but considers doubling at the fuseway a no no yet doubling immediately after the consumer unit (say the first fitting) is OK. I realise he`s unhappy that people often get two lighting circuits (say upstairs and downstairs) then combine them to be one circuit is a bit naughty (not good practice usually) but if someone redesigns it as such then it becomes only one circuit. 
The word "minimise" when talking about circuits is a misnomer too though because the only way to minimise is to put each point on its own circuit and none of us do that. Spreading ccts out to reduce disruption when losing a cct is what we usually do. and again its up to the cct designer, not always good designs though I`m afraid and I do realise that is what he is trying to avoid. I must admit when I see such I always think "has someone put two ccts in one fuseway as a cheap way of freeing up a way for something else thereby comprising , a little, a decent design. It often is, although I`d avoid the comment "circuits doubled" 
I'm afraid your "friend" should NOT be an approved contractor. Reason: complete lack of basic knowledge. Just imagine his EICR, total disaster!
Zoomup. Interesting comment, do you work for a manufacturer of RCBOs? I have a split CU and MCBs in my own house. I have had no nuisance trips, or in fact any at all in the last 5 years, except occasionally when I plug in my tool transformer! Of course my installation and appliances have no faults either, this nuisance trip thing is due to faults and bad appliances. Why go mad and add more RCDs for no extra protection from anything? "Oh dear my freezer went off because it was faulty, or the kettle was", is surely a good thing? It seems you want to perpetuate bad practice which is to ignore problems. A tripped RCD needs investigation and understanding, it is the first indication that something is not quite right. An RCBO might trip and not be noticed if the circuit has nothing else attached.That is actually a problem! If you have 10 RCDs in an installation rather than one the chance of a failure is ten times as great. Is that a good thing? I am not sure that it is.

Just in case you think I only have "nice" loads, this is not true. I have 4KW VSDs, all the usual appliances, RF filters, loads of SM psus and computers. Earth leakage is still < 10mA.

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